


Causa latet, vis est notissima (The cause is hidden, the result obvious)

by Cotidie_morimur



Category: Shingeki no Kyojin | Attack on Titan
Genre: After the fall of the titans, Aged-Up Character(s), Anal Fingering, BDSM, Biting, Blindfolds, Bondage, Bottom Levi (Shingeki no Kyojin), Cock Warming, Dom/sub, Gentle Dom Eren, Hand Feeding, Kink Negotiation, M/M, Plot What Plot/Porn Without Plot, Potential dub-con (not between main characters), Slight mention of pain, Sparring, Sub Levi, Subspace, dom eren
Language: English
Status: Completed
Published: 2021-01-08
Updated: 2021-01-08
Packaged: 2021-03-18 16:54:17
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,655
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28621374
Author URL: https://archiveofourown.org/users/Cotidie_morimur/pseuds/Cotidie_morimur
Summary: After the titans have been defeated everyone is able to relax for the first time in years, that is everyone except Levi, who only seems to get more and more irritated. Fed up, Eren talks to Levi to find out what's going on. Surprisingly, there's more to it than he thought...
Relationships: Levi/Eren Yeager
Comments: 3
Kudos: 210





	Causa latet, vis est notissima (The cause is hidden, the result obvious)

**Author's Note:**

> Let me know if there are any tags I missed. This is set after the titans have been defeated. Any kudos and comments are much appreciated!

Levi is irritable. Ok well, _more_ irritable than usual. Eren can see it in the way he’s less tolerant of the squad’s tomfoolery, snapping at them for minor transgressions. Its… odd to say the least. 

It all comes to a head during training. Eren and Levi are sparring. It’s a dirty fight, both literally and metaphorically. They’re covered in mud from head to toe, thick, sticky mud. Levi is quick and strong, able to get under Eren’s defenses, but Eren knows him, knows how he moves. Years on a battlefield fighting together will do that. Levi has always refused to pull his punches, always but now there are… hesitations. They’re minute but there.

Levi hears a crunch as Eren’s elbow hits his side. Snarling, he spins around, a vicious roundhouse kick aimed at Eren’s head. Eren ducks, hooking his foot around Levi’ ankle to trip him. Levi stumbles back, off balance. Eren steps forward to get a jab in but Levi’s already recovered, spinning away. 

“Running away, short stuff?” Eren smirks.

“What did I say about talking when you’re fighting brat?” Levi throws a punch at Eren but it’s slow. Eren frowns and feels a piercing pain in his foot as Levi slams his foot down on Eren’s foot. Off-balance, Levi easily knocks him onto his back, pinning him in the mud.

“To not do it?” Eren smirks up at Levi. He waits a moment until he can feel Levi relax then he moves, twisting so that Levi is pinned.

Levi looks disgruntled, his hair splayed out around his head and absolutely caked with mud. There it is. Eren sees it, the hesitation. Eren knows for a fact that Levi can get out of this pin but maybe it’s not a question of _can’t_ , it’s a question of _want_. Levi is avoiding his gaze.

“What’s the matter? You’ve been acting weird.” Eren’s voice is soft and he relaxes the pin so that he’s barely holding on. Eren swears he can hear a soft whine when he does. 

“Nothing’s wrong” Levi’s still not looking him in the eyes. 

Eren pushes himself up until he’s sitting cross-legged on Levi’s stomach. “Oh really?” His tone is dry. “You’re more grumpy than usual, I relaxed my pin and you didn’t take the opportunity, the other have noticed too.” He wipes some of the grime of Levi’s face. “We’re worried, Captain.”

Levi can feel his face flushing and is reluctantly grateful for the layer of mud coating his cheeks, blocking Eren from seeing it. No matter how nice the feeling of Eren on top of him was, he shoves Eren beside him on to the ground.

“It’s too fucking muddy. Meet me in my quarters in half an hour. Get every speck of mud off of you or so help me I will _end_ you.” His long-forgotten attraction to the Captain sparks a heat low in his stomach. He’d held a torch for the Captain back when he was a cadet, but years of fighting and camaraderie had extinguished said torch.   
“Aye-aye Captain.” Eren directs a lazy salute in Levi’s direction then heads off to the barracks to shower and change.

Precisely 30 minutes later Eren finds himself standing outside of Levi’s room hand poised to knock.

“Come on in brat.” Eren scoffs and pushes the door open. Levi is curled in the armchair, lounging with a mug of tea, cupped against his stomach. The aroma of black tea wafts towards Eren.

“You’ll be up all night if you drink that now.”

“I’ll be up all night anyways”

Eren hums noncommittally, looking around the small room. It’s dusty, Eren realizes with a start.

“Clearly there’s something wrong.” Eren frowns. “It’s dusty in here. What’s up.”

“Just… give me a second brat” Levi snaps at him. Then sighs. “You tell no one Eren.” Levi’s eyes were cold. He was dead serious. “You tell anyone, and I mean anyone, I will cut up your body and hide the pieces where no one will ever find them.” Levi pulls the mug closer to his chest, it softens something tight in his chest. “You remember what you learned about dynamics in training right?”

The memory is hazy, but Eren thinks he remembers most of it. “The majority of the population are switches, very few are dominants, and even fewer are subs.”

“Right. Do you remember anything else?”

“I’m getting to it, cool your jets. For the most part dynamic doesn’t really affect daily lives but if subs don’t get put into subspace and if dominants don’t put subs into subspace then they get irritable and moody, among other symptoms.” Eren thinks that’s most of it.

“It also causes them to lose their appetite and disrupts their circadian rhythm” Levi adds. There’s a feeling in his stomach that tells Eren where this is going, but he needs Levi to say it.

“I’m a sub.” Levi isn’t looking him in the eyes.

“Ok, and?”

“What makes you think there’s an and?”

Eren pins Levi with a glare.  
“And.” Levi draws it out, looking at him. “I haven’t dropped in months. That’s why. Nothing big.”

“What changed?”

“What?”

“What changed? Why haven’t you dropped?”

“I don’t know? I just can’t?” Levi squirms, embarrassed. “I can usually make myself go down but now every time I’ve tried I just… Ugh”

“And you didn’t try and find someone to help you?”

Levi growls. “It didn’t work.”

“Not to pry too much—” Levi mutters something under his breath that sounds suspiciously _like you’ve already pried_. “But how did they try to get you down?” Eren’s face flushes. “I don’t need details.”

“Pain usually”

“And is that what you usually do?”

“Fuck myself until my brain shuts off.”

“Jesus” Heat curls in Eren’s stomach.

“Can I try to help you go down?” Eren’s voice was hushed and reverant. Eren was looking at him with care in his dazzling green eyes. This was unusual. The others had all looked at Levi like he was a piece of meat. “I want to help Levi. Let me help.”

“Give me a moment to think.” Levi manages to stammer out.

“Alright” Eren said, smiling at him.

That easy acceptance of his need for space was what made the decision more than anything. If Eren did actually managed to get him into subspace, he knew that when he came back up he’d still be the same in Eren’s eyes, not weak, not lesser.

“Ok.” Levi nodded. “You can try.”

It’s the next day and Eren is once again standing in front of Levi’s door. They had arranges to meet back here so they could discuss their new arrangement. Eren wanted to give this to him, to let him rest, to calm him. He couldn’t wait.

He knocks once.

“Come in brat.” Levi calls from inside the room.

Eren walks in and grabs a chair, positioning it in front of Levi’s armchair. 

“Come sit Levi, there are some things we need to talk about.” Levi emerges from the kitchen clutching another piping-hot mug of tea in his hands. He sprawls himself into the chair in a surprisingly undignified manner.

“You said yesterday that people usually use pain to try and get you go down. Did you…want that? Like that?”

Levi hums.

“Words please” Eren’s rebuke was gentle.

“At the time, I felt like it was necessary. I wouldn’t want to do it again.”

“Good.” The praise sends a warm feeling down Levi’s spine.

“What are your safewords?”

“I usually use the traffic light system.”

“How do you feel about being touched? Touching? Anywhere you don’t want to be touched?”

“I fucked up my shoulder a few years ago, twisting or pulling on it really fucking hurts. Other than that, I like being touched and am fine with touching you.”

“Good. I’m quite happy to touch you and be touched. What about sex? Do you have any preferences?”

“I’m fine with most things, just don’t go anywhere near my ass with your tongue.”

“Aye-aye captain.” Eren give him a teasing look.

They continue to discuss their limits and some potential scenes. Eventually, Levi gets antsy at the sheer amount of talking that Eren was making them do and he says as much.

“I think for all our sakes we should try this today, huh short stuff?” Eren raises an eyebrow.

“Confident aren’t you brat.” Levi’s arms fold and he pouts.

“I’ve got to go grab a few things; I’ll be right back.” Eren ruffles his hair before leaving the room.

Eren is carrying a bag full of… something when he gets back.

“You ready?” Eren’s eyes are soft. 

Levi nods, overwhelmed.

“Words please.”

Levi swallows thickly. “I’m ready.”

“Then I’d like you to strip please.” Eren’s voice is cool and commanding.

Levi is stunned at his boldness. His hands shake as he pulls at his cravat and button-up. In his rush to strip he flings his clothes somewhere behind him.

“Fold them please. That’s not any way to treat your belongings.”

When Levi turns back, Eren is sitting in his chair, a pillow at his feet. 

“Come kneel for me.” Eren holds out his hand to Levi. Levi bites his lip as he walks over, taking Eren’s hand. “You’re being so good for me” Heat suffuses Levi’s body and he looks down. Fuck, Eren was really trying to kill him. He kneels carefully on the cushion in front of Eren. Eren gently grabs the back of Levi’s neck, guiding his head towards Eren’s thigh. He can feel the heat of Eren’s legs around him, he felt surrounded and safe. “Colour?”

“Green” Levi’s mouth feels dry.

“Good. Close your eyes and open your mouth.” Levi can’t help but obey. He feels the familiar tendrils of subspace clouding his brain. Eren puts something sweet on Levi’s tongue and he sucks on the chocolate in his mouth, humming in contentment. Eren nudges his lips with another piece of rich dark chocolate. Levi eagerly opens his mouth for more and Eren chuckles, placing the piece of chocolate on his tongue. Eren’s fingers linger on his tongue and he licks at them, whining for more. “Shush love.” His fingers stroke Levi’s tongue. “So good for me.”

Levi can feel himself sinking deeper, only tethered by the fingers in his mouth and the heat of Eren’s leg against his side. Eren cards his hand through Levi’s hair while he floats, occasionally offering him more chocolate. 

When Levi comes back to himself, he’s sitting in Eren’s lap. His head is tucked snugly against Eren’s shoulder, hands clinging to his shirt. He blinks sleepily up at Eren, who is smiling down at him. 

“So…”

Levi grumbles when Eren holds a glass of water to his lips.

“Nope, no whining. Drink.” 

Levi drinks. 

“So… did I do a good job? Can I put you down again?”

Levi purses his lips. “You did a good job.” He sighs. “Thank you, I feel much better. If…” He looks away in embarrassment, his cheeks flushing. “If you want to put me down you can.” Eren smiles, cuddling Levi. They spend the rest of the afternoon relaxing together, content in each other’s presence. Levi feels at ease for the first time in months, the restless energy under his skin calm.

Their relationship remains, much to Levi’s chagrin, stubbornly platonic. That is, until one day. They’re reading together in his room, Eren in the armchair and Levi sprawled on the bed. Levi couldn’t concentrate on his book though, his thoughts kept distracting him. Eventually Levi gives up, thumping his book down heavily on the bedside table. Eren looks up at the sudden noise.

“Are you ever going to fuck me?” The words spring from his mouth without conscious thought.

“Do you want me to fuck you?” Eren raises an eyebrow.

“Of course I do.” Levi furrows his eyebrows. Eren snorts in amusement. 

“Strip for me.” Levi hurries to comply folding his clothes and haphazardly putting them on the floor.

Suddenly, Eren is very close to him. He can feel Eren’s eyes on him, pinning him in place. He shivers lightly as he feels a hand curl possessively around his hip. Levi’s breath catches in his throat. Eren steps forward, pressing the length of his body against Levi’s. Levi reflexively takes a step back and he collides with the wall. His breath rushes out in shocked exhale.

“Colour?” Eren’s voice was soft.

“Green” Levi stammers when he finally musters enough breath.

Eren runs his hand gently down Levi’s side, stroking the curve of his hip and cupping his strong thigh. 

“Here’s whats going to happen.” Eren eyes are half lidded as he stares down at him. “I’m going to tie you down to your bed and tease you until you beg me to come. Sound good?”

Levi chokes on his own spit. “Please.” He whines.

“Already begging?” Eren smirks. “I’m better than I thought.” He pulls Levi towards him, hooking one of Levi’s leg over his hip. Levi presses up against Eren’s thigh, grinding against him. Levi glares at him, pulling desperately at his shirt.

“Shut up.” Levi scrunches his eyes closed as Eren kisses him, hungry and all-consuming. Eren kisses down his neck, nuzzling gently against the junction between his neck and shoulder. Levi can feel Eren smile against his skin before pressing a soft kiss to that spot. Then, Eren is gone. Levi feels bereft and cold, shivering from the loss. Levi can’t help but whine pitifully. 

“On the bed.”  
Levi pants as he walks over to the bed, striving for nonchalant but probably failing. He looks back over his shoulder at Eren, uncertain where Eren wants him. 

“On your back.” Eren is walking towards him holding a silky green rope. Levi sits awkwardly on the edge of the bed, laying back on the bed. Eren nudges open his legs, standing between his legs. Levi taps his fingers together idly until Eren stills his hands. 

“Colour?”

“Green.” Levi presses up against Eren’s hand. 

Eren hums as he grabs Levi’s wrists, running his thumbs against the pulse points. 

“Keep your hands right here for me.” He positions Levi’s wrists where he wants them. As Eren wraps the rope around his wrists, he closes his eyes letting the sensation wash over him. He hums contentedly. Eren ties off the rope, testing Levi’s circulation. Eren runs his hands lightly up Levi’s arms. Levi shivers at the teasing touch.

“Maybe I should blindfold you.” Eren’s voice was teasing. “Make you hold your breath, not knowing where or when I’d touch you next.” Levi lets out a long drawn out whine. Damn, he wants that. “Words please.” 

“I… Yes please.” Levi opens his eyes to look at Eren, pleading with him. 

“Mmmmm.” Eren squeezes his shoulders. “Go sit up against the headboard for me, love.”

Levi scrambles up the bed, his movements made awkward by his tied hands. Levi watches Eren walk over to his bag, grabbing a long length of fabric. 

“So good for me.” Eren smiles. Levi can feel his face flush as heat curls around his stomach. Kneeling beside Levi, Eren ties the fabric around his head, brushing his hair out of the way.

“Good?” Eren’s hand settles at the nape of his neck. Levi hums his assent.

“Words.” Eren’s hands tightens on the back of his neck. Levi goes boneless at the touch, leaning into Eren’s hand. 

“Good.” Levi groans. “Get on with it.” He hears Eren laugh.

There’s a rustling of movement and Levi is pushed against the headboard. There are rough hands on his shoulders, pressing against the tense muscles. 

“Relax. Let me make you feel good.” He can hear Eren’s voice whicpering in his ear. 

Eren starts kissing along his shoulder and Levi relaxes into the feeling until Eren bites down, worrying a bruise into Levi’s skin. Keeping one hand on his shoulder Eren kisses down Levi’s body, following the curve of his body. He presses a kiss to the middle of Levi’s chest, using his other hand to tweak Levi’s nipple. It startles a shout out of Levi, jerking at the sudden sensation. 

“Colour?” Eren’s voice is concerned.

“Green.” Levi growls, desperate to continue. Eren mouths at Levi’s other nipple letting it pebble and harden under his tongue as he toys with the other in his hand. Eren bites down hard and Levi keens, curling around Eren’s head. Stroking his hand down Levi’s side, he switches the attention of his tongue to the other nipple, toying at it and biting it. Eren grabs Levi’s hip in a solid grip, pressing him down onto the bed. Eren kisses down across Levi’s trembling stomach, laving his tongue across the strong muscles. Eren nuzzles into the jut of Levi’s hips, biting gently along the bone. 

“Ok love. Lie down for me.” Levi scrambles to obey. Eren settles between his parted legs, lifting his thighs onto Eren’s knees. “Gorgeous.” Eren bites large bruises into Levi’s trembling thighs, completely ignoring Levi’s cock.

“Get on with it.” Levi whines. 

“Whatever you say.” Levi can hear a cap snapping open as Eren drizzles lube on his fingers. “What would you rather?” Eren grabs Levi’s dick, rubbing his thumb under the head of his dick. “Here?” Then the touch is gone, and he feels a long, slow rub against his fluttering hole. “Or Here?”

Levi’s toes curl as he whines, long and drawn out. “Wherever you want.”

Eren hums, pressing on the bruises on Levi’s thighs as he thinks. The hand is back at Levi’s hole, teasing at the rim. Eren slides one finger gently inside, kissing at Levi’s stomach, resolutely ignoring Levi’s cock. Eren’s finger is stroking the walls of Levi’s hole, tracing his thumb around the rim.

“So greedy.” Eren teases. “I bet you could take my entire hand if we really tried. Can you imagine that? Split open for me, desperate for more.” Levi shoves himself down on Eren’s finger searching for more. “Oh, you like that don’t you? The idea of being fucked on my hand? Stretched around my fist?” Levi moans, long and loud. Eren adds another finger, pressing upwards to nudge Levi’s prostate. Levi bucks his hips and Eren follows, pressing mercilessly against Levi’s prostate. Levi can feel Eren’s thumb pressing against his perineum, massaging Levi’s prostate from both angles. Levi gasps at the pleasure filling him, his cock hard and insistent, dripping precum onto his stomach. His awareness focuses until he’s focused solely on Eren’s hands on his body. He can feel himself become incoherent, his head getting fuzzy and heavy.   
Moans are falling freely from Levi’s lips now and he’s squirming on the bed wanting it to never end but simultaneously desperate to come. Eren grips his cock, thumbing under the head. Levi grits his teeth.

“More.” Levi grounds out.

Eren hums, gripping Levi’s cock lightly, still not stroking the way Levi wants. “I don’t know Levi, have you been good for me? Do you deserve to come?”

Levi hisses. “I’ve been good.” 

“You want to be even better for me?” In that moment Levi desperately wanted to be good. “Then beg.”

“Fuck.” Levi scrunches up his face. “Please Eren. Please, I’ve been so good. Please let me come.” His last few worlds were drawn out into a whine as Eren finally strokes him properly. Levi gasps as Eren firmly tugs on his cock while pressing mercilessly into his prostate and before he knows it, he feels the splash of hot cum on his stomach. 

Levi collapses bonelessly onto the bed. 

“I’m going to get a cloth to clean you up.” Eren says, gently removing his fingers from Levi’s ass. Levi whines at the loss. Levi lets himself float in the hazy headspace until Eren returns, wiping his stomach gently with the cloth.

“I’m going to undo the cuffs now Levi.” The rope loosens and drops away from his wrists. Eren rubs the red indents from the rope to return circulation to his hands. “And the blindfold.” The fabric drops and Levi blinks in the low light of the room. Eren is smiling at him. “Come sit with me.” Eren sits against the headboard patting the bed between his legs. Levi crawls over to him, settling between his legs. Eren hooks his chin over Levi’s head as his arms tighten around Levi, holding Levi tight to his chest. 

Eren holds some chocolate to Levi’s mouth and Levi gratefully accepts, savouring the sweet treat. Levi dozes in Eren’s arms occasionally being offered a drink or some food. Eventually, Levi settles fully back into his body. As he does, he notices the hard line of Eren’s cock against his back.

“You didn’t come?” Levi asks.

“This was about you, not me” Levi can feel Eren shrug behind him. 

“Can I?” Levi cuts himself off. “Can I sit on your cock?”

Eren sits quietly for a moment, a bolt of heat shooting through him at the thought. “Wouldn’t that be uncomfortable for you?” 

“I just want to be full? If that makes sense.” Eren pulls him closer and noses against his neck.

“Of course, love.” Eren kisses his neck, letting go so Eren can pull down his pants to free his cock. It springs out, hard and flushed. Eren uncaps the lube, spreading it on his cock. Eren guides Levi’s hips until his cock was pressed teasingly against Levi’s hole. 

“Hurry up.” Levi glares back at Eren.

Eren hushes him and lets him gently slide down Eren’s cock until he settles at the base. 

Levi sighs in satisfaction. “Shit, that feels good.” Eren’s cock is stretching him in the best way, full and warm within him. Eren stifles a laugh against Levi’s shoulder. 

“So what do you want to do now?” Eren mumurs against his skin. 

“Hmmmm. You could read to me?”

Eren snorts and leans over to grab Levi’s book off the bedside table. He reads, drawing idle patterns on Levi's side until they both drop off to sleep.


End file.
